Conventionally, there are some integrated circuit (IC) chips that have to operate over a wide ranging voltage supply (VDD). For example, the voltage supply may range from a lower value of 2.7 volts (V) to a higher value of 5.25V. As such, the wide ranging voltage supply can present some different challenges for implementing different circuitry within IC chips. Additionally, within this category of IC chips, there are some IC chips that also include both digital logic circuitry together with analog circuitry within the same chip. It is noted that there are disadvantages associated with these type of IC chips.
For example, a grouping of digital logic circuitry on an IC chip may create current spikes on a power supply line that is also utilized or shared by some analog circuitry. As such, it is appreciated that these resulting current spikes can temporarily or consistently “contaminate” the proper operation of one or more elements of the analog circuitry.
One conventional solution for “decoupling” the voltage supplied to the digital logic from the voltage supplied to the analog circuitry is to include an RC (resistor capacitor) filter circuit as part of the IC chip. The RC filter circuit is typically located between the voltage supply and the digital logic circuitry in order to reduce the occurrence of current spikes on the voltage supply line. Additionally, the analog circuitry can receive its voltage supply directly from a voltage supply pin of the IC chip. However, there are disadvantages associated with this conventional solution.
For example, since the voltage supply to the digital logic covers a wide range of voltages, the RC filter circuit may not operate very well over that entire voltage range. Typically, the resistance of the RC filter is determined such that it does not provide too much attenuation to the low supply voltage levels while providing enough resistance to reduce the size of the current spikes on the voltage supply line at the high supply voltage levels. Therefore, to enable the RC filter to operate over the entire voltage range of the supply voltage, the RC filter is commonly implemented with a resistance value that sacrifices an amount of operational performance at some voltage supply levels within the voltage range.
The present invention may address one or more of the above issues.